| 摘要 |
<p>PURPOSE:To improve the reliability by efficiently performing the screening of excess erasure as the defective mode peculiar to a flash memory. CONSTITUTION:In the normal erasure test, a collective erasure S3, excess erasure defect discrimination in a CB test S4, and PASS/ FAIL discrimination by a black check S5 are executed; and after the normal collective erasure S3, an additional erasure S9 and S10 are performed, and thereafter the CB test and the blank check are executed, thereby increasing the stress at the time of erasure to easily detect an excess erasure bit. Thus, bits latently having an inclination of excess erasure are completely screened in the early stage to improve the reliability of a non-volatile semiconductor storage device.</p> |
